'Make or break'

Holding a photo of Maxine, she said: "We are disappointed but we are pragmatic - it is what we expected."

Twenty-one people were killed when bombs exploded at the Mulberry Bush and Tavern in the Town on 21 November 1974

It was the first time she and other members of her family had met the chief constable after first contacting him in 2009.

21 November, 1974

At 20:17 GMT a bomb exploded in a duffel bag in the Mulberry Bush pub in the Rotunda, Birmingham, killing 10 people

Ten minutes later, at 20:27, a second bomb went off in the Tavern in the Town, killing 11 more and injuring 182

A third bomb outside a bank on the Hagley Road failed to explode

West Midlands Police's Counter Terrorism Unit has been reassessing evidence connected with the original 1974 inquiry as well as material from the Court of Appeal and other documents.

Mr Sims said 18,500 items had been collated and preserved, 9,000 of which were analysed.

"My professional judgement is that the 1991-94 investigation was carried out to a good standard," he said.

"I am sorry that families were not kept up to date or engaged with, as is standard practice today. Forty years ago was a different era and a different force."

Mr Sims said the case was not closed because "it is always possible that brand new and significant information could become available to us".

'Biggest unsolved murder'

Birmingham Six

Within hours of the explosions six Irish men were arrested - they later became known as the Birmingham Six

Paddy Hill, Gerry Hunter, Johnny Walker, Hugh Callaghan, Richard McIlkenny and Billy Power were jailed for life in August 1975

The case was referred to the Court of Appeal, but the convictions were upheld in 1988

The convictions were quashed at London's Old Bailey in March 1991

BBC correspondent Anthony Bartram said there were angry scenes at West Midlands Police headquarters as the two sides argued over whether the entire Hambleton group, including two lawyers, would be allowed into the meeting.

Maxine's brother Brian Hambleton said: "Chris Sims has just rubber-stamped the fact that terrorists can come up to Birmingham, kill people and walk away.

"Birmingham is a soft touch for terrorists to come and carry out their arts, and they know the worst-case scenario is they might get arrested and sent to prison, they won't be sentenced to death."

Julie Hambleton described the bombings as England's "biggest unsolved murder of the 20th Century" and vowed to "continue to fight until justice is done".

"We're fighting for those who aren't here to fight for themselves," she said.

The two bombs went off 10 minutes apart in pubs a few yards from each other

She said that the police had told her 35 pieces of evidence were missing, including a third device that failed to explode on the night of the bombings.

Mr Sims said the force assumed the items had been disposed of in the 1980s "on the basis the case had been completed".

He said: "That feels utterly at odds with current procedure but was probably not as unusual at that time.

"We're not able to trace back when it happened and who was responsible."

Paddy Hill, who was one of six men wrongly jailed over the bombings, said he was angry but it was "what I expected".

He has set up an online petition calling for an independent inquiry.

He said: "I've said before to the relatives of those who died none of us are never ever going to get justice, it's a big cover-up.

"If we can get 100,000 signatures on the petition then we will be able to get a public inquiry or something. The truth is the very, very least we deserve."

The Birmingham Six spent nearly 16 years in jail before their convictions were quashed